TPS54260: RT / CLK input waveform

Hi

My customer has question.

The customer inputs an external clock to RT / CLK. (External clock = 3.3V)
When checking the RT / CLK waveform with the TPS54260 activated, the clock has no margin against the threshold (2.2V).
Increasing the external clock voltage is not possible due to the possibility of exceeding the rating.
Is there no problem in this state?
If there is a problem, I think I need to adjust the external constant. Is there a suitable constant?

TPS54260_CLK.pdf

Best Regard

T Kishi